Various radio communication systems complying with the 3GPP (Third Generation Partnership Project) standards have been utilized. In radio communication systems complying with the LTE/SAE (Long Term Evolution/System Architecture Evolution) standards among the 3GPP standards, user equipments execute communication with external networks (such as the Internet) via eNBs (evolved Node Bs), which are base stations, and gateways (SAE Gateways).
The communication is executed via logical paths established between nodes within the radio communication system. More specifically, a user equipment exchanges user data (such as voice data, picture data, etc.) with an external network via a data radio bearer, which is a logical path established between the user equipment and a base station (eNB), and an S1-U bearer, which is a logical path established between the base station (eNB) and a gateway. Logical paths used for user data communication are referred to as user plane paths (U-plane paths). Control of user plane paths (establishment, change, release, etc.) is conducted by the initiative of an MME (Mobility Management Entity), which is a switching station. For example, an S1-U bearer is established by that the switching station controls (exchanges control signals with) the base station (eNB) and the gateway that will be endpoints of the S1-U bearer. Exchange of control signals are executed via a control plane path (C-plane path), which is a logical path for control established between nodes.